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Speces related

  1. Nov 4, 2007 #1
    A very simple question I am struggling about, I don't know how to determine two species are related. Is it only the similarity in the genetic sequences ?

  2. jcsd
  3. Nov 4, 2007 #2
    I think I should ask ALL of my questions so that I won't keep asking


    Is there also a strange problem as when 3 or 4 species having the same degree of similarity in their compared sequences ? (please don't laugh at my question :-( )
  4. Nov 5, 2007 #3

    jim mcnamara

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    Staff: Mentor

    For plants and animals it usually is:
    1. similarity of reproductive organs (flowers, ovaries, etc..)
    2. similarity of DNA sequences of course - this is called cladistics
    3. Specific conservative phenotypic values (visible traits) - like mammalian teeth or the structure of the pelvis. This is used with non-living species - fossils.

    #2 is the gold standard, but until we have that for every existing species we go with number 1, and secondarily things like #3.
    Last edited: Nov 5, 2007
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